During the Computex 2019 event, Noctua presented its prototype of passive cooling, which weighed 1.5 kg and could passively conduct heat at 120W or 180W with silent fans on the housing.
The prototype had a mounting capability for both the AM4 and LGA 115x socket, and the cooler was able to keep the Intel i9-9900K processor cooled under full load.
Noctua is working hard to release a commercially available passive CPU cooler during the first quarter of 2021. This cooling was recently noticed in a photo, published by @FanlessTech, and it is suggested that it will soon enter mass production.
Noctua is expected to release more details about this passive CPU cooler in the coming months.